Difference between anyMatch and findAny in java 8

Question

I have an Array and want to perform some matching on it's element.

I came to know that it could be done in two ways in java 8 :

String[] alphabet = new String[]{"A", "B", "C"};

anyMatch :

Arrays.stream(alphabet).anyMatch("A"::equalsIgnoreCase);

findAny :

Arrays.stream(alphabet).filter("a"::equalsIgnoreCase)
        .findAny().orElse("No match found"));

As I can understand both are doing the same work. However, I could not found which one to prefer?

Could someone please make it clear what is the difference between both of them.

Solution

They do the same job internally, but their return value is different. Stream#anyMatch() returns a boolean while Stream#findAny() returns an object which matches the predicate.

Comments

[Jorn Vernee]

They almost do the same work. anyMatch is a short-circuit operation, but filter will always process the whole stream.

[Dariusz]

@JornVernee are you entirely certain of that statement? As far as I remember streams are "lazy", which, for sequential streams, means that after encountering the first matching value in anyMatch it will be returned and the filter will not be processed further.

[Jorn Vernee]

Hmm, I suppose you are right. At least it depends on the implementation. I'm going of the documentation here, where only anyMatch explicitly mentions that it's a short-circuit operation.

[Eugene]

@JornVernee findAny code : if (!stop && predicate.test(t) == matchKind.stopOnPredicateMatches) { stop = true; ... it is short-circuiting.

[Jorn Vernee]

@Eugene is that the JDK9 implementation? The findAny I have doesn't accept a predicate

[Eugene]

@JornVernee that's the third time this week! :( yes, it is jdk-9; that's the default I have. sorry

[Jorn Vernee]

@MehrajMalik Well, it's supposed to come out on 2017/07/27 That's not too long from now.

[Dariusz]

@JornVernee I checked, take a look at stackoverflow.com/questions/44180155/…

[Eugene]

@JornVernee you might have some "substance" here. One is implemented via FindOps and the other via MatchOps. It could have been easily done so that match would call find and just return isPresent on the resulting Optional. I just know I will not be able to sleep normally until I understand why...